Current-rectifying apparatus.



R. P. JACKSON.

CURRENT REGTIPYING APPARATUS.

APPLICATION FILED MAB. 9, 1908.

"931,124. A Patented Aug. 17,1909.

WITNESSES:

IN ENTUR RAY r; lmcKsoN,

UNITED. STATES PATENT orrrcn.

OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO WESTINGHOUSE ELECTRIC & MANUFACTURING OOMPAN Y, OF EAST PITTSBURG, PENN- SYLVAN IA, A CORPORATION OF PENN SYLVAN IA.-

GURRENT-EECTIFYING APPARATUS."

Specification of Letters Patent.

Patented Aug. 17, 1909;.

Application filed March 9, 1908. Serial No. 420,064.

citizen of the United States, and a resident devices, inductive resistances are of Wil-kinsburg, in the county of Allegheny and State of Pennsylvania, have inventeda new and" useful Improvement in Current- Rectifying Apparatus, of which the following is aspecification.

My invention relates to current-rectifying a'pparatusand particularly to transformers that constitute parts of such apparatus.

The object of the invention is to provide a transformer of such structure and arrangement of parts that all other auxiliary devices may be dispensed with and regulation of the operation of the rectifier be readily effected.

In the charging of storage batteries from mercury-vapor or similar current-rectifying usually included in the direct current circuits for the purpose of sustaining the. rectified currents,

and the charging of the batteries is regulated by causing suitable drops of potential in the system, either by introducing ohmic resistance into the direct current circuit or by introducing inductance into the alternating current circuit.

In order to reduce the number of pieces been proposed to so construct and arrange the parts of the transformer from which the rectifying deviixe is supplied that no additional means need be employed for; sustaining the former, however,

, or for considerable rectified current or for regulating the charging operation of the battery. By reason of the specific construction of the said transit is not well adapted for numbers of battery cells, ranges of battery voltage, such as occur at different degrees of charge of. the battery, and it is accordingly the object of the present invention to provide a transformer that shall be better adapted for such service.

Figure l of the accompanying drawing is a diagrammatic view of a system embodying the invention, and Fig. 2 is a simplified diagram of the same system.

A storage battery 1', of any desired number of cells, is supplied with charging current from current-rectifying apparatus comuse with varying 'termediate of a suitable number of prising a mercury-vapor or'similar rectifying device 2 and a transformer 3. The transformer comprisessix series-connected coils 4, 5, 6, 7, 8, and 9 that constitute the secondary winding, the extremities thereof being connected respectively to. alternating Clll'lc it terminals 10 and 11 of the rectifying device 2, and the neutral or some other suitable inpoint of the Winding being connected to one terminalof the battery. The other terminal of the battery is connected to the negative or direct current terminal 1-2 of the rectifying device.

The coils 5 and 8 are subdivided by means leads thatare respectively connected to stationary contact terminals 13 to 24, inclusive, of a regulating device 25 comprising, further, a movable arm 26 carrying conducting members 27 and 28 which are adapted to engage the said contact terminals, as well as conducting segments 29 and 30 that are disposed adjacent thereto and are connected to circuit conductors 31 and 32. The active length of the transformer winding included between the.

ciicuit conductors, which constitutes the primary winding, may, therefore, be varied by adjusting the position of the arm 26.

he magnetizable core of the transformer 3 comprises a rectangular portion 34 upon opposite'sides or legs of which the coils 4. to 9, inclusive, are mounted, three coils surrounding each leg, and an auxiliary central portion or leg 35 extending, between the coils, from. top to bottom and from side to side of the main core portion 34:, air-gaps of suitable widths being provided between the adjacent edges of the core portions. The. auxiliary coreportion 35 provides, between the coils, leakage paths of relatively low and suitable reluctance and such that the primary winding, or a part thereof, wil} be surrounded by.a leakage flux that does not also surround all of the secondary Winding,

and, further, such that the secondary win ing, or a part thereof, will be surrounded by a leakage flux that does not also surround the primary winding. The effect of the former flux is to cause I potential in the system, and the eifect o t e latter isto sustain the, rectified current.

the desired dro ,of

parts 'ing effect may remain stant, itis desirable which serves to sustain the rectified current transformer;

The arrangement of the coils and core with respect to eachother is, in addition, such ,that in making changes in the active length of the primary winding, 71. 6., changes in the voltage applied to the direct current circuit, the distribution and amounts fluxes will.be so affected as to cause the leakage Volts per turn of the winding surrounding the primary leakage "flux to vary in substantially the same ratio as the primary and secondary volts per turn, with the result that the power factor of the rectifying apparatus remains approximately uniform under. all conditions of operation. In order, also, that the amounts of current supplied to the substantially the same range for. each step of the regulator, it is desirable thatthe drop of potential in the system remain an approximately constant percentage of the secondary voltage, andin order that the minimum hmiting value of the direct'current at which the rectifying operation will continue may be approximately the same for each step of the regulator, 2'. e., in order that the sustainapproximately conthat the leakage flux should vary approximately in proportion to variations -in the secondary voltage of the The structure and arrangement of the parts of the transformer, as shown, aresuch as to secure these results.

When beginning the charging operation, the connections should be arranged to 1'0- duce a low secondary voltage', because 0 v the low voltage of the batteryin its uncharged "condition, and, accordingly, the regulator 'cated,

arm'26 should occupy the position in providing, of course, that the battery comprises the minimum number of cells which the apparatus is adapted to charge. The primary winding then comprises all of coils 5, 6, 8, and 9, thefmain' flux produced therebyjtraversing a path indicated by the broken line 37, its direction during a given half cycle being indicated by the pointers 38. The secondary flux opposes the main primaryjflux, and, by reason of the relatively low reluctances of the leakage paths provided by the core portion 35, rimary leakage fluxesthat do not surroun the whole of 1 the secondary winding are caused to traverse paths indicated by the broken lines 39 and 40. These" leakage fluxes have the same effect as the presence of inductive resistance between the transformer and the supply circuit, or of the-presence of ohmic resistance in the direct current circuit, 2'. e., of causing a drop of-potential in the system for regu- "lating purposes.

. ever, do. not have any sustaining efiect upon the rectified to shift the phase of the alternating current current, sincethey simply serve with to the electromotive force.

battery may vary through 7 from falling By reason of the opposition of'the primary and secondary fluxes, "secondary leakage fluxes are also caused to traverse the relatively low'reluctance paths provided by the core portion 35, the said aths being indicated, during one-half cyc e of the alternating current, by the. lines 41 and 42, and during the other half cycle by the lines 43 and 44.

the core art 35 in the same direction for each hal cycle of the alternating current. There is, therefore, no necessity of reversing the magnetism, or of fully re-magnetizing the said portion of the magnetic circuit, with the result that the increase of current in each half of the secondary. winding will be but slightly delayed. On the other hand, the decrease of current in each half of the secondary winding is considerably delayed by reason of the energy previously stored there- .by in the portions of the magneticcircuit bythe secondary leakage I that are traversed I fluxes, with the result that the uni-d rectional or rectified currents, that are derived from the respective halves of the secondary It will be observed thatthe secondary eakage fluxes traverse the central portion of winding during successive half cycles of the alternating current, overlap. The secondary leakage flux, therefore, has the same effect as the presence of inductive resistance in the direct current circuit, 5. e., of sustaining the direct or rectified current or of preventing it below a definite or. predetermined value. The leakage fluxes indicated by the lines 41 to 44, inclusive, have no efiect in causing a drop of potential in the system, because the direction of the said fluxes in the core portion 35 does not change.

As the battery becomes charged, its voltage increases an the amount of charging current accordingly decreases. current delivered to the battery has decreased to a predetermined value, the sustaining 'efi'ect afforded by the leakage fluxes indicated by the lines 41 to 44, inclusive, becomes insuflicient to sustain the rectified current, and the rectifying process, therefore, interrupted. If the battery is not, at that time, fully charged, the regulator arm 26 should be moved another step in a clockwise direction for the purpose of removing portions of'the coils 5 and 8 from the primary circuit of the transformer, which, in turn,-

serves to increase the voltage applied to the secondary circuit. In general, the mode of operation remains as previously described,

though, upon removing portions of the coils 5 and 8 from the primary circuit of the transformer, a greater amount ofprimary leakage flux is caused to traverse the path indicated by the line 39 and a smaller amount to traverse the path indicated by the line 40, while the total amount of leakage is increased.-

- The changes in the amount and distribution of the leakage fluxes are such that the leakage volts per turn of the Winding surrounding the primary leakage fiux change substantially in direct proportion to the change in the primary and secondary volts per turn, and also such that the change in the sustaining effect afforded by the fluxes indicated by the lines 41 to 44, inclusive, is substantially proportional to the changes in the secondary voltage. The power factor of 1e apparatus, therefore, remains substantially the same as before the movement of the regulator arm and the rectifying operation will continue until the rectified current has decreased to substantially the same value as that at which the operation ceased before movement of the regulator arm.

If the battery cannot be fully charged with the conducting members 27 and 28 in engagement with contact terminals 14 and 23, respectively, the regulator arm should be moved step by step in a clockwise direction until the desired degree of charge is obtained. In continuing the movement of the regulator arm in aclockwise direction, he total amount of primary leakage flux increases and more of the flux indicated by the line 40 is gradually diverted into the path indicated by the line 39, with the result that the conditions above described continueto prevail.

The range of direct current voltages obtainable from the apparatus is such, or ma be such-in practice, charge a storage battery the voltage of which may change considerably from nocharge to fully-charged condition, or to adapt it for use in the charging of batteries comprising considerably different numbers of cells. system is proportional to the product of the primary leakage flux and the number of turns of the winding surrounding this flux, this result would not occur if the distribution of the leakage flux were not altered at the same time that it is changed in amount, or at the same time that the secondary voltage is changed.

. While theinvention is primarily intended for use in connection with the charging of storage batteries, it is not limited to such use,

but is equally "applicable in connection with apparatus employed for other purposes.

I claim as my invention: 1. A transformer comprising subdivided coils, and leakage paths of relatively lew reluctance between the coils, in combination with means for varying the points-of connection to the subdividedcoils, and a current rectifying device supplied from the transformer, the coils and leakage paths of the transformer being so arranged with respect to each other that upon varying the points of connection to the coils the sustaining effect upon the rectified current afforded as to adapt it to fully Since the drop of potential in the able core having two ,pointsof connection to the by the transformer will vary substantially in proportion to variations in the secondary voltage.

2. A transformer comprismg subdivided coils, and leakage paths of relatively low repoints of confactor of. the apparatus will remain substantially uniform and th the rectified current former will vary substantiallyin proportion to variations in the secondary voltage.

In a transformer, the combination of 'a winding affording primary and secondary circuits, means'for varying the active length of one of the transformer circuits, and leakage paths of relatively low reluctance between ihe coils arranged to cause variations in the distribution of the leakage fluxes with variations in the active length of the said transformer circuit.

4. A transformer comprising a magnetizable core having two legs, a plurality of coils surrounding each. core leg, those occupying intermediate positions being subdivided, and leakage paths of relatively low reluctance between the coils.

5. A transformer e sustaining effect upon comprising a magnetizlegs, a plurality of coils surrounding each core leg, those occupying intermediate positions being subdivided, and leakage paths of relatively low reluctance between the coils, in combination withmeans for adjusting the points of connection to the subdivided coils. I f 6. A. transformer comprising subdivided coils, and leakage paths 'of relatively low reluctance between the ceils, in combination with means for yarying thepoints of connection to the subdivided coils, the coils and leakage paths beingso arranged with respect to each other that, upon varying'the afforded by-the transcomprising a plurality 'of coils coils, variations in the distribution of the leakage fluxes are also effected.

7. A transformer comprising subdivided coils, and leakage paths of relatively low reluctance between the coils, in combination with means for varying the points of con-- nection to the subdivided coils, the coils and leakage paths being so arranged with respect to each other that, as the volts per turn of the primary and secondary windings are varied, proportionate variations are effected in the leakage volts per turn of the winding surrounding the primary leakage flux.

8.,A transformer comprising subdivided coils, and leakage paths of relatively low relnctance-between the coils, in combination In testimony whereof, I have hereunto with means for varying the points of consubscribed my name this 27th day of Feb- 10- nection to the subdivided coils, the coils and ruary, 1908.v leakage pa hs being so arranged'with re- 5-spect to each other that, upon varying the i )oints of connection to the coils, the power W'itnesses: actoi of the transformer will remain sub- R. B. INGRAM, stantially uniform. BIRNEY HINES.

RAY P. .iAoKsoN. 

